The present invention generally relates to an improvement of a method of manufacturing a heat exchanger which may be utilized for a heat exchanging ventilation arrangement or the like for reducing heat loss during ventilation and more particularly, to a method of manufacturing a heat exchanger in which a laminate prepared by piling many sheets one upon another so that the neighboring sheets may be formed with bonded portions and non-bonded portions, is expanded in such a direction that the respective sheets are spaced from each other so as to define flow channels or passages between the sheets at the non-bonded portions, and which employs the steps of printing patterns of bonded material onto the sheets, laminating the sheets, and subsequently expanding the laminate to form the heat exchanger.
Generally, heat exchangers employed for heat exchanging ventilation arrangements, etc. are broadly divided into heat exchangers of a rotary type and those of a stationary plate type. With respect to materials for elements of the heat exchangers as described above, there have generally been employed such materials as paper, metals, plastics, ceramics, etc.
Various constructions are presently employed for the elements. For example, in the case of a total heat exchanger intended to reduce heat loss during ventilation, for rotary type heat exchangers, there is mainly adopted such a construction that a corrugated board prepared by overlapping a flat sheet S1 over a corrugated sheet S2, is wound into a spiral shape in the form of a disc matrix as shown in FIG. 1 or a construction in which a metallic wire or moisture absorbing natural fibers formed into a net-like structure is employed as a heat exchanging medium (not particularly shown). On the other hand, with respect to a stationary plate type heat exchanger, there is generally employed a construction as shown in FIG. 2 in which corrugated boards each prepared by alternately overlapping partition sheets S3 and corrugated spacing sheets S4 each other, are piled up in turn one upon another so that a primary air flow fa and a secondary air flow fb may be alternately passed through the respective layers between the partition plates S3.
The conventional heat exchangers as described above, however, have such disadvantages that the pressure loss thereof is high, shaping at end faces thereof tends to be troublesome, and cost is generally high.